1. Field of the Invention
The present invention relates to a positive active material, a positive active material composition for a lithium-sulfur battery and a method of preparing the positive active material composition, and more particularly, to a positive active material for use in a lithium-sulfur battery having a high capacity, a positive active material composition and a method of preparing the positive active material composition.
2. Description of the Related Art
A positive electrode of a lithium-sulfur battery is generally prepared by mixing a sulfur compound as a positive active material, a conductive agent, and a binder in a solvent to prepare a slurry, and coating the slurry on a collector. To exhibit good conductivity, the sulfur compound and the conductive agent should be uniformly distributed in the solvent. However, it is easy to prepare a slurry in which the sulfur compound and the conductive agent do not disperse uniformly. This non-uniformity causes the deterioration of the conductivity of the resulting positive electrode and requires a larger amount of the conductive agent than an amount otherwise necessary. The increased amount of the conductive agent requires a larger amount of the binder than otherwise required due to the large specific surface area of the conductive agent. Consequently, the amount of the positive active material decreases relatively in the slurry, thereby reducing capacity. In addition, even though a large amount of the conductive agent is used, the positive electrode has poor charge and discharge characteristics.